Fair Value Measurements (Fair Value Unobservable Inputs) (Details) $ in Thousands	3 Months Ended	12 Months Ended
	Mar. 31, 2024 USD ($) holding	Dec. 31, 2023 USD ($) holding
Fair Value, Option, Quantitative Disclosures [Line Items]
Cash Payment For Contingent Consideration Obligation	$ 4,600
Re-sign Broker Dealers
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent consideration	182	$ 4,232
Re-sign Broker Dealers | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent consideration	207	4,826
Deposit Program Growth
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent consideration	11,568	11,568
Deposit Program Growth | Maximum
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent consideration	$ 12,500	$ 12,500
Probability of Achievement | Re-sign Broker Dealers
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent Consideration, Measurement Input | holding	0.990	0.990
Probability of Achievement | Deposit Program Growth
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent Consideration, Measurement Input | holding	1.000	1.000
Payment Term (in years) | Re-sign Broker Dealers
Fair Value, Option, Quantitative Disclosures [Line Items]
Payment Term (in years)	1 year 7 months 17 days	1 year 10 months 17 days
Payment Term (in years) | Deposit Program Growth
Fair Value, Option, Quantitative Disclosures [Line Items]
Payment Term (in years)	9 months	1 year
Discount Rate | Re-sign Broker Dealers
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent Consideration, Measurement Input | holding	0.0640	0.0640
Discount Rate | Deposit Program Growth
Fair Value, Option, Quantitative Disclosures [Line Items]
Contingent Consideration, Measurement Input | holding	0.0640	0.0640